Multilayered color photographic material

ABSTRACT

IN A MULTILAYERED COLOR COLOR PHOTOGRAPHIC MATERIAL AT LEAST ONE OF THE THREE COLORED PARTIAL IMAGES IS PRODUCED IN A DOUBLE LAYER CONSISTING OF TWO LIGHT-SENSITIVE SILVER HALIDE EMULSION LAYERS, BOTH CONTAINING A COLOR-FORMING COUPLER FOR THE SAME PARTIAL IMAGE. ONE OF THE PARTIAL LAYERS, PREFERABLY THE UPPER ONE, IS MORE SENSITIVE TO LIGHT THAN THE OTHER BY FORM 0.1 TO 0.6 LOG I.T UNITS. THE COLORFORMING COUPLER IN THE MORE LIGHT-SENSITIVE LAYER COUPLES FROM 2 TO 20 TIMES MORE RAPIDLY THAN THAT IN THE LESS SENSITIVE LAYER. THE NECESSARY RATIO OF COUPLING VELOCITIES CAN BE ACHIEVED BY THE METHODS USED FOR INCORPORATING THE COUPLERS IN THE LAYERS. THE MATERIAL EXHIBITS LESS GRAININESS AND HIGHER SENSITIVITY.

United States Patent 3,726,681 MULTILAYERED COLOR PHOTOGRAPHIC MATERIALGerrit Pankow, Opladen, and Bernhard Morcher, Rigobert Otto, and ErickBockley, Leverkusen, Germany, assignors to Agfa-GevaertAktiengesellschaft, Leverkusen, Germany No Drawing. Filed Nov. 9, 1970,Ser. No. 88,224 Claims priority, application Germany, Nov. 22, 1969, P19 58 709.8 Int. Cl. G03c 1/76 US. Cl. 96-74 2 Claims ABSTRACT OF THEDISCLOSURE In a multilayered color color photographic material at leastone of the three colored partial images is produced in a double layerconsisting of two light-sensitive silver halide emulsion layers, bothcontaining a color-forming coupler for the same partial image. One ofthe partial layers, preferably the upper one, is more sensitive to lightthan the other by from 0.1 to 0.6 log 1.! units. The colorformingcoupler in the more light-sensitive layer couples from 2 to 20 timesmore rapidly than that in the less sensitive layer. The necessary ratioof coupling velocities can be achieved by the methods used forincorporating the couplers in the layers. The material exhibits lessgraininess and higher sensitivity.

The invention relates to a multilayered color photographic material inwhich at least one of the partial color images, is to be produced in adouble layer.

As is well known, a multilayered color photographic material constructedin the usual manner in accordance with the theory comprises ared-sensitive silver halide emulsion layer which is arranged lowermoston a support of for example paper, cellulose ester or polyester andwhich contains a cyan-forming coupler incorporated in this layer in sucha manner that it is resistant to diffusion. On this layer there isapplied a green-sensitive layer which has a magenta-forming couplerincorporated in it. This is followed by a yellow filter layer and lastlya top layer which contains a yellow-forming coupler and which is usuallynot sensitized, i.e. it is only sensitive to the blue region of thespectrum. If desired, however, the arrangement of layers in a colorphotographic material may be reversed.

An increase in the sensitivity of multilayered color photographicmaterials is achieved, as described in British patent specification No.818,687, if the emulsion layer which is directly applied to the supportconsists of two partial layers arranged one on top of the other,provided that the lower layer consists of a less sensitive silver halideemulsion and the upper layer consists of a highly sensitive silverhalide emulsion. Both layers contain colorforming couplers in the sameconcentration and are sensitized to the same region of the spectrum. Amaterial of this type has, however, the disadvantage in that theincrease in sensitivity is accompanied by an increase in the graininess.This is an important consideration, especially for films which are usedfor taking photographs of originals, because it reduces the limit ofmagnification.

In order to overcome this disadvantage and to lower the graininess ofthe color images, in the process described in German Pat. No. 1,121,470the layer which contains the more highly sensitive and coarser grainedemulsion is adjusted to a lower color density than the less sensitivelayer.

Belgian Pat. No. 713,806 describes a process for improving the sharpnessof the image, according to which the two layers which are sensitized tothe same region of the spectrum contain different couplers, the morehighly sensitive emulsion layer containing so-called 4-equivalentcouplers and the less sensitive layer so-called Z-equivalent couplers.

Both processes have numerous disadvantages, for example in the processaccording to German Pat. No. 1,121,- 470 the sensitivity of the emulsionis not fully utilized, especially if the emulsion is processed asreversal material. In negative color development, 2-equivalent couplersnaturally produce a higher color fogging in the unexposed parts of theimage than 4-equivalent couplers, and in addition they produce apronounced color graininess due to the high intensifying effect in colordevelopment described in German Pat. No. 1,002,198.

The need, therefore, remained to improve the sensitivity and lower thegraininess of the known color photographic materials in which at leastone of the partial images, is to be produced in a double layer.

It is an object of the invention to provide a color photographicmaterial which will have a very high sensitivity and will give rise tocolor images of great sharpness and, if possible, little graininess.

A multilayered color photographic material has now been formed for theproduction of colored images consisting of a yellow, a magenta and acyan partial image, in which material at least one of the partial colorimages is to be produced in a double layer comprising a highly sensitivesilver halide emulsion layer and a less sensitive silver halide emulsionlayer, both of which layers contain a color-forming coupler for theparticular partial image. In this color photographic material, thehighly sensitive emulsion layer is more sensitive by from 0.1 to 0.6 log1.2 units than the less sensitive emulsion layer, contains acolor-forming coupler for the particular partial image which couplesfrom 2 to 20 times more rapidly than the color-forming coupler in theless sensitive layer, and is preferably arranged above the lesssensitive layer.

In multilayered color photographic materials, other layers may beinterposed between the less sensitive and the more highly sensitivesilver halide gelatin emulsion layer of a pair of layers for theproduction of a partial color image, e.g. one of the layers of a pair oflayers for the production of another partial color image.

The ratio of coupler to silver may be different in the two layers of apair. In a color negative material, the ratio of coupler to silver inthe highly sensitive layer is preferably lower than in the lesssensitive layer. In the case of reevrsal materials, the ratio of couplerto silver in the highly sensitive layer is preferably greater than inthe less sensitive layer, for example 1.5 to 5 times greater.

The suitability of color-forming couplers for the preparation of thematerial acording to the invention does not depend on their chemicalstructure, although it is, of course, important that the couplers in thetwo layers of the pair should absorb substantially in the same region ofthe spectrum. Chemically, the color-forming couplers need not beidentical. The important factor in every case is the ratio of couplingvelocities of the color-forming couplers if incorporated in the layer.

According to the present invention the more sensitive emulsion layercontains the coupler with the higher coupling velocity and the lesssensitive layer contains the coupler with the lower coupling velocity.

The coupling velocity of the couplers used can also be modified by themethod used for incorporating the couplers in the emulsion layers. Forexample, a coupler which is incorporated in the emulsion in form of asolution in high boiling solvents, so-called oilformers, couples moreslowly than the same coupler if incorporated in the absence ofoilformers. Hence, follows, in a simple way, the

possibility to achieve the desired ratio of coupling velocities of thecouplers used in the layer pairs. Couplers to be incorporated withoutoilformers are dissolved, as is known, in a low boiling solventevaporating off as the layer dries, so that the coupler is presentundissolved in a separate phase in the layer. Therefore, according to apreferred embodiment of the invention, the same coupler can be used inboth partial layers of a double layer, but incorporated in the moresensitive layer in the absence of, and in the less sensitive layer inthe presence of, an oilformer.

Couplers which are useful for the present invention with respect to theratio of their coupling velocities can also be selected making use ofthe fact that in the layers hydrophilic water-soluble color-formingcouplers couple more rapidly than hydrophobic color-forming couplerswhich are heterogeneously dispersed. Thus, for example, difiusion-fastcolor-forming couplers may be used both having the same basic structure,but one containing a water solubilizing group and being present indissolved form as the more rapidly coupling compound in the more highlysensitive silver halide emulsion layer, while the heterogeneouslydispersed hydorphobic coupler containing no water solubilizing group isincorporated in the less sensitive silver halide emulsion layer as thecoupler with the lower coupling velocity.

Colored color-forming couplers may also be used according to theinvention, these being introduced into the layer either alone ortogether with a colorless coupler having the same or at least a similarcoupling velocity.

Optimum sensitivity and color graininess are obtained if thecolor-forming coupler in the less sensitive layer couples more slowly bya factor of from 3 to 5 than the coupler in the more highly sensitivelayer. If the difierence in coupling velocities is substantially higherthan the factor of from 3 to 5, it may be advantageous for the sake ofobtaining a straight lined gradation curve to add a rapidly couplingcoupler to the slow coupler, but the proportion of rapid coupler shouldnot exceed 50% by weight.

Methods for determining coupling velocities are known. Particularly, themethod of J. Eggers for determining the relative coupling velocitiespublished in Mitteilungen aus den Forschungslaboratorien der AgfaLeverkusen Miiuchen, Volume III, page 81 ('Springer-VerlagBerlin-G6ttingen--Heidelberg, 1961) has proved to be very useful forchoosing suitable color-forming couplers.

Rapidly coupling and slowly coupling couplers in the sense of thepresent invention can be selected also by means of simple tests. Rapidlycoupling couplers are such couplers, which in the same emulsion exhibitthe same constant threshold sensitivity independent of the quantity ofcoupler used. The sensitivity is defined as the log Lt-value of thegradation curve measured at the density 0.2 above fog. Slowly couplingcouplers in the sense of the present invention exhibit a sensitivityclearly dependent on the quantity of coupler.

Examples of suitable slowly coupling and rapidly coupling color-formingcouplers for the three substractive primary colors cyan, magenta andyellow are summarized in the table below.

(I) COUPLERS WHICH HAVE A RELATIVELY HIGH COUPLING VELOCITY Cyan-formingcouplers:

1C1 OH IC-i Magenta-forming couplers:

IMl

Yellow-forming coupler:

(II) SLOWLY COUPLING COLOR-FORMING COUPLERS II 01 0 H o o N-CHz-Q I NHCO0 11 HO 0 0 -o 0 OH 1102 OH HQCITICIEHH @4; ONHO l E s 03H I&OCH3

H03 0 H N lBHffl Magenta-forming couplers:

IIM1

i HO 0 O -CHzCONH i NH IIM2 i C -CnHas HOaS \N/ \O/ Yellow-formingcoupler:

IIYI

The following examples illustrate the invention. The given parts are byweight throughout the examples:

EXAMPLE 1 Photographic material 1 Relatively slowly couplingmagenta-forming couplers in both partial layers.

60 parts of a 0.1% methanolic solution of the green sensitizer:

CaHs

40 parts of a 1% aqueous solution of 4-hydroxy-6-methyl-l,3,3a,7-tetraazaindene and 240 parts of a aqueous solution ofthe magenta-forming coupler IIM3 are successively stirred at 40 C. into1000 parts of a fine grained silver iodobromide gelatin emulsion ofmedium sensitivity containing 8% by weight of gelatin, 3.5% by weight ofsilver bromide and 0.3% by weight of silver iodide.

The mixture is cast on a layer support of cellulose triacetate anddried. The dry layer has a thickness of 3p. and contains 1.2 g. ofsilver in the form of silver halide per m 60 parts of a 0.1% methanolicsolution of the aforesaid green sensitizer, 40 parts of a 1% aqueoussolution. of 4-hydroxy-6-methyl-l,3,3a,7-tetraazaindene and 75 parts ofa 5% aqueous solution of magenta-forming coupler -IlM3 are stirred into1000 parts of a highly sensitive silver iodobromide gelatin emulsioncontaining 9.6% by weight of gelatin, 3.7% by weight of silver bromideand 0.2% by weight of silver iodide, at 40 C.

The mixture is applied to the aforesaid green-sensitive layer and dried.The second layer has a silver application of 1.4 g. of silver in theform of silver halide per m Photographic material 2 Green-sensitivedouble layer containing rapidly coupling magenta-forming couplers inboth parts of the ayer.

The same quantities of green-sensitizer and of stabilizer are stirredinto 1000 parts of the above-mentioned silver iodobromide emulsion ofmedium sensitivity, and in addition 480 parts of a 2.5% aqueous solutionof magentaforming coupler 1M1. The mixture is applied to a layer supportof cellulose triacetate and dried. When finished,

Green-sensitive double layer according to the invention having a slowlycoupling color-forming coupler in the less sensitive silver halideemulsion layer and a rapidly coupling color-forming coupler in thehighly sensitive silver halide emulsion layer.

The highly sensitive silver bromide emulsion layer of material 2 isapplied on the silver iodobromide emulsion layer of medium sensitivityof material 1 and dried.

Processing.--The double layered materials described above are exposedbehind a green filter in a conventional sensitometer behind a grey stepwedge with a logarithmic density increase of 0.15 per step, and thematerials are then processed as follows:

Minutes (1) Color-forming development 7 3 g. of diethylamin anilinesulfate 1 g. of hydroxylamine hydrochloride 2 g. of sodium sulfite 2.5g. of potassium bromide 75 g. of sodium carbonate dissolved in watermade up to 1000 ml.

Minutes (2) Washing 20 (3) Bleaching bath 5 g. of potassium ferricyanidedissolved in water made up to 1000 ml. (4) Washing 5 (5) Fixing bath 5g. of sodium thiosulfate dissolved in water made up to 1000 ml.

The results obtained from the sensitometric interpretation aresummarized in the table below.

This example also covers comparisons between various double layeredmaterials containing color-forming coupiers of particular couplingvelocities in the two parts of the double layer.

Material 1 Red-sensitive double layer containing slowly couplingcyan-forming couplers in both parts of the layer.

70 parts of a 0.1% methanolic solution of the red sensitizer:

2H5 30 parts of a 1% aqueous solution of4-hydroxy-6-methyll,3,3a,7-tetraazaindene and 190 parts of an 8% aqueoussolution of cyan-forming coupler IIC3 are introduced with stirring at 40C. into 1000 parts of a fine grained silver iodobromide gelatin emulsionof medium sensitivity which contains 9.8% by weight of gelatin, 3.2% byweight of silver bromide and 0.2% by weight of silver iodide. Theemulsion is applied to a layer support of cellulose triacetate anddried. The dry layer contains 1.5 g. of silver in the form of silverhalide per mfi.

The above-mentioned quantities of red sensitizer and of stabilizer areadded at the same temperature to 1000 parts of a highly sensitive silveriodobrornide gelatin emulsion containing 8% by weight of gelatin, 3.7%by weight of silver bromide and 0.2% by weight of silver iodide, and inaddition 60 parts of an 8% aqueous solution of the same cyan-formingcoupler are stirred in. The emulsion is applied to the layer describedabove and dried. The second layer contains 1.3 g. of silver in the formof silver halide per m5.

Material 2 Red-sensitive double layer containing rapidly couplingcyan-forming coupler in both parts of the layer.

The same silver iodobromide gelatin emulsion of medium sensitivity asdescribed in the case of material 1 is prepared but instead of using thecyan-forming coupler mentioned there, 250 parts of a 6% aqueous solutionof cyan-forming coupler 1C3 are stirred in. The emulsion is againapplied to a layer support of cellulose triacetate and dried. Thefinished layer contains 1.2 g. of silver in the form of silver halideper 131.

The same quantities of red sensitizer and stabilizer are added to thehighly sensitive silver iodobromide emulsion of material 1, and inaddition 80 parts of a 6% aqueous solution of the above-mentionedcyan-forming coupler 1C3 are stirred in. The emulsion is applied to thelayer of medium sensitivity mentioned above and dried. The finishedlayer contains 1.1 g. of silver in the form of silver halide per m.

Material 3 Red-sensitive double layer containing a slowly couplingcyan-forming coupler in the layer of medium sensitivity and a rapidlycoupling cyan-forming coupler in the highly sensitive layer.

The highly sensitive silver iodobromide emulsion layer of material 2 isapplied to the silver iodobromide emulsion layer of medium sensitivityof photographic material 1 and is dried. The two layers contain thequantities of silver halide per m. mentioned above.

Processing-The photographic materials 1, 2 and 3 are exposed in aconventional sensitometer behind a red filter and a grey step wedge witha logarithmic density increase of 0.15 per step, and are then processedas described in Example 1.

The results of the sensitometric interpretation are summarized in thefollowing table.

It is seen from the table that, like in Example 1, material 3 has boththe advantage of fine graininess of material 1 and the advantage ofincreased sensitivity of material 2.

EXAMPLE 3 Blue-sensitive double layered materials are compared in amanner similar to that used in the previous examples.

Material 1 Blue-sensitive layer containing slowly coupling yellowformingcouplers in both parts of the layer.

30 parts of a 1% aqueous solution of 4-hydroxy-6-methyl-l,3,3a,7-tetraazaindene and 450 parts of a 5% aqueous solution ofthe yellow-forming coupler IIYI are stirred into 1000 parts of thesilver iodobromide emulsion of medium sensitivity of Example 1 at 40 C.The emulsion is applied to a layer support of cellulose triacetate anddried. When finished, the layer contains 1.7 g. of silver in the form ofsilver halide per m.

The stabilizer solution mentioned above and 180 parts of a 5% aqueoussolution of the same yellow-forming coupler are introduced with stirringat 40 C. into 1000 parts of the highly sensitive silver iodobromideemulsion of Example 1. The emulsion is applied to the aforesaid emulsionlayer of medium sensitivity and dried. The highly sensitive layercontains 1.8 g. of silver in the form of silver halide per m.

Material 2 Highly sensitive double layer with rapidly couplingyellow-forming couplers in both parts of the layer.

The same quantities of stabilizer and 450 parts of a 5% aqueous solutionof the rapidly coupling yellow-forming coupler IYl are stirred into 1000parts of the silver iodobromide gelatin emulsion of medium sensitivityused for material 1. The emulsion is again applied to a layer support ofcellulose triacetate and dried. The finished layer contains 1.4 g. ofsilver in the form of silver halide per m.

The same quantities of stabilizer and 180 parts of a 5% aqueous solutionof the aforesaid yellow-forming coupler are stirred into 1000 parts ofthe highly sensitive 10 silver iodobromide emulsion of material 1. Theemulsion is applied to the aforesaid layer of medium sensitivity and thewhole material is dried. The highly sensitive emulsion layer contains1.55 g. of silver in the form of silver halide per m..

Material 3 spond to those obtained in Examples 1 and 2. The material 3is just as fine grained as material 1 in every part of the image but hasthe same sensitivity as material 2, which is higher than that ofmaterial 1, namely 0.3 logarithmic I .2. units.

EXAMPLE 4 Comparison of double layered materials in one of which thesame color-forming coupler is introduced into both layers at differentconcentrations but by the same method, whereas in the other the samecolor-forming coupler is introduced into the two-layers by differentmethods.

Material 1 Coupler introduced into both layers by the same method.

The same parts of green sensitizer and of stabilizer and in addition 360parts of a dispersion of color-forming coupler in gelatin are added to1000 parts of the silver iodobromide emulsion of medium sensitivity ofmaterial 1 of Example 1. The emulsion is applied to a layer support ofcellulose triacetate and dried. The finished layer contains 1.2 g. ofsilver in the form of the silver halides per m.

The dispersion of color-forming coupler in gelatin is prepared asfollows: 20 parts of the magenta-forming coupler IM3 are dissolved in 40parts of dibutyl phthalate and the dispersed in 300 parts of a 5%aqueous gelatin solution.

parts of the above described dispersion of colorforming coupler ingelatin are added to 1000 parts of the highly sensitive silveriodobromide emulsion of material 1 of Example 1 which has beensensitized and stabilized in the same manner. This mixture is applied tothe above layer of medium sensitivity and dried. The second layercontains 1.4 g. of silver in the form of the silver halides per m9.

Material 2 Color-forming coupler incorporated by different methods.

The silver iodobromide emulsion of medium sensitivity is prepared in thesame way as described above for material 1 and then applied to a layersupport and dried.

parts of a dispersion of coupler in gelatin which contains the samecolor-forming coupler but no high boiling solvent (oil-former) are nowadded to 1000 parts of the above-mentioned highly sensitive silveriodobromide gelatin emulsion which has been sensitized and stabilized inthe same manner. The dispersion of coupler in gelatin is prepared asfollows:

10 parts of the same magenta-forming coupler 1M3 are dissolved in 30parts of ethyl acetate and then dispersed in 150 parts of a 5% aqueousgelatin solution.

The above emulsion mixture is applied to the silver iodobromide emulsionlayer of medium sensitivity and 1 1 dried. On drying, the ethyl acetateused as solvent for the color-forming coupler evaporates and the coupleris left in the solid form in the layer, The second layer contains 1.4 g.of silver in the form of the silver halides per m? after drying.

Processing.Materials l and 2 are exposed and processed as described inExample 1.

Sensitometric measurements show that material 2 has the graininess butis more sensitive by 0.2 log I.t units than material 1. This is due tothe fact that the colorforming coupler present in solid form in thehighly sensitive silver iodobromide emulsion layer in material 2 conplesmore rapidly than the color-forming coupler emulsitied in dissolved formin the highly sensitive emulsion layer of material 1.

EXAMPLE In the following example dififerent double layers are comparedin color photographic reversal processing.

Material 1 The two parts of the double layer diifer in their sensitivitybut both parts contain the same magenta-forming coupler at the sameconcentration.

400 parts of a 5% aqueous solution of the magentaforming coupler IIM3are added to 1000 parts of the silver iodobromide gelatin emulsion ofmedium sensitivity of material 1 of Example 1, which has been sensitizedto the green region of the spectrum and stabilized in the same manner.The emulsion is applied to a cellulose triacetate support and dried. Thedry layer contains 1.2 g. of silver in the form of the silver halide perm.

The highly sensitive silver io dobromide gelatin emulsion of material 2from Example 1 is now applied to their layer of medium sensitivity atthe same silver concentration per m The emulsion was sensitized to thegreen region of the spectrum in the same manner and contained the samestabilizer. It also contained 400 parts of a 5% aqueous solution of themagenta-forming coupler IIM3.

Material 2 Double layer containing slowly coupling magentaformingcoupler in the layer of medium sensitivity and a rapidly couplingmagenta-forming coupler in the highly sensitive layer; the ratio ofcoupler to silver is approximately the same in both layers.

The same silver iodobromide emulsion layer of medium sensitivity isprepared as for material 1. The highly sensitive silver iodobromidegelatin emulsion layer from EX- ample l is applied to the aforesaidlayer at the same silver concentration per m? and dried. The moresensitive emulsion had been sensitized to the green region of thespectrum in the same way as described in Example 1 and contains the samestabilizer. It also contained 800 parts of a 2.5% aqueous solution ofthe magenta-forming coupler IMl.

Material 3 Double layer containing a slowly coupling magenta formingcoupler in the layer of medium sensitivity and a chemically differentrapidly coupling magenta-forming coupler in the highly sensitive layer;the ratio of coupler to silver is considerably higher in the highlysensitive layer.

180 parts of a 5% aqueous solution of magenta-forming coupler IIM3 areadded to 1000 parts of the silver iodobromide gelatin emulsion layer ofmedium sensitivity from Example 1, which layer has been sensitized tothe green region of the spectrum in the same manner and contains thesame stabilizer. The emulsion is applied to a cellulose triacetatesupport and dried. The finished layer has a silver concentration of 1.8g. of silver in the form of silver halide per m. The ratio of coupler tosilver is 0.23.

The highly sensitive silver halide layer of material 1 is applied to theaforesaid silver iodobromide gelatin emulsion layer of mediumsensitivity. The ratio of coupler to silver in this highly sensitivesilver halide layer is 0.51.

Processing.-The three double layered materials are exposed in aconventional sensitometer behind a green filter and a grey step wedgewith a logarithmic density increase of 0.15. They are then all processedidentically by the color photographic reversal process described inPhotographic Chemistry by P. Glafkides, Volume 2, pages 631 and 632published by the Fountain Press, London.

The three double layered materials all have substantially the samemaximum density. In the sensitornetric interpretation, the point on thegradation curve situated 0.2 density units below the maximum density ischosen for comparing the sensitivities.

The comparison shows that materials 2 and 3 are more sensitive by about0.25 log Lt units than material 1. The magenta image of material 3 has asubstantially finer grained structure than the color images obtainedwith the two other materials.

EXAMPLE 6 In this example the properties of the double layered materialsof Examples 1 to 3 are compared in the context of a color photographicmultilayered material.

Color photographic material 1 The following layers are applied to acellulose triacetate layer support as described in Examples 1 to 3:

(a) the red-sensitive double layer of material 1 according to Example 2,

(b) an intermediate gelatin layer,

(c) the green-sensitive double layer of material 1 according to Example1,

(d) an intermediate gelatin layer,

(e) a yellow filter layer containing colloidal silver as filter dye,

(f) the blue-sensitive double layer of material 1 according to Example3.

Color photographic material 2 The material is built up in the same wayas the aforesaid material 1 but the double layers of material 2according to Examples 1 to 3 are applied.

Color photographic material 3 The material is built up in the same wayas the aforesaid material 1 but the double layers of material 3 fromExamples 1 to 3 are used.

Processing-Processing is carried out as described in Example 1, butexposure in the sensitometer is carried out with white light behind agrey step wedge.

The results of sensitometric interpretation from Examples 1 to 3 areconfirmed here. Materials 2 and 3 have a higher sensitivity by about 0.3log I.t units and material 3 in addition has the excellent fineness ofgrain of material 1.

What we claim is:

1. In a multilayered silver halide emulsion negative color photographicmaterial for the production of a combination of images each image havingits own color different from that of each of the other images, and inwhich material there is a pair of silver halide emulsion layers for atleast one of the images, both emulsion layers of a pair containing acolor-forming coupler for the particular color of that image, theimprovement according to which one of the emulsion layers of a pair ismore sensitive by 0.1 to 0.6 log [.1 units than the other, its couplercouples from 2 to 20 times more rapidly than that of the other, isarranged above the other, and has a coupler-to-silver 13 1.4 ratio lessthan that of the other, and the color couplers FOREIGN PATENTS of thephotographic material are all 4-equivalent cou- 923 045 4/1963 GreatBritain plers. l

2. The combination of claim 1 in which the more rapid NORMAN TORCHINPrimary Examiner color coupler couples from 3 to 5 times more rapidly 5than the slower color coupler. J. R. HIGHTOWER, Primary ExaminerReferences Cited US. Cl. X.R. UNITED STATES PATENTS 96-67 3,516,8316/1970 Wolf 96-74

